Pressure sensors are used in automotive vehicles for a variety of purposes, for example, sensing the vacuum pressure at the intake manifold of a vehicle engine.
One known type of pressure sensor, described in an article by Oakes which appears in the proceedings of the Third International Conference on Automotive Electronic, 143-9, 1981, and is entitled "A Pressure Sensor for Automotive Application ", Mechanical Engineering Publications, London, England, page 354, ISBN 085298 477 4, comprises a pressure sensing element, including a piezoresistive silicon semiconductor chip, and a separate semiconductor integrated circuit (IC) for receiving an electrical signal from the sensing element, processing the signal, and generating the output signal from the sensor. In this known sensor, the sensing element is completely enclosed in its own sub-package which includes outwardly extending terminals permitting electrical access to the enclosed sensing element. The sub-package is entirely enclosed, in turn, in the main package of the pressure sensor. The main package includes an inport which communicates directly with an opening in the sensing element sub-package permitting exposure of the sensing element to the pressure to be sensed.
The signal processing IC is also mounted within the package main housing and electrically connected to the terminals of the sensing element sub-package by wire bonds. Finally, wire bonds interconnect terminal portions of the signal processing IC to terminals of the main package.
It is desirable to improve such known sensor in four principal areas, namely: the differential operating temperature between the pressure sensing element and the signal processing element, size, simplicity of construction and fabrication, and cost.